Adhesive bonding and miscellaneous chemical manufacture – Surface bonding means and/or assembly means therefor – Tire body building type
Reexamination Certificate
2002-03-11
2004-12-07
Knable, Geoffrey L. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Surface bonding means and/or assembly means therefor
Tire body building type
C156S416000, C156S417000
Reexamination Certificate
active
06827119
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an improved radially expansible tire assembly drum (
10
) and a method for forming tires (
2
) from an assemblage of tire components utilizing the assembly drum (
10
).
BACKGROUND OF THE INVENTION
Historically, the pneumatic tire has been fabricated as laminated structure of generally toroidal shape having beads, a tread, a belt reinforcement and carcass. The tire is made of rubber, fabric, and steel. The manufacturing technologies employed for the most part involve assembling the many tire components from flat strips or sheets of material. Each component is placed on a building drum and cut to length such that the ends of a component meet, or overlap, creating a splice.
In the first stage of assembly, the carcass would include one or more plies, and a pair of sidewalls, a pair of apexes, an inner liner (for a tubeless tire), a pair of chafers and perhaps a pair of gum shoulder strips. Annular bead cores can be added during the first stage of tire building, and the ply or plies can be turned around the bead cores to form the “ply turnups.”
Typically, the carcass components (excluding the bead cores) would be either “butt spliced” or “lap spliced.” A butt splice has the component ends joined, but not overlapped. A lap splice has overlapping ends.
This intermediate article of manufacture can be cylindrically formed at this point in the first stage of assembly. The cylindrical carcass is expanded into a toroidal shape after completion of the first-stage of tire building. Reinforcing belts and the tread are added to the intermediate article during a second stage of tire manufacture, which can occur using the same building drum or work station or at a separate shaping station.
During the expansion of the carcass, tensile stresses are imposed on the spliced and uncured components of the tire carcass.
In the case of automobile or light truck tires, lap splices were preferred because the splice remained intact, whereas butt splices would tend to open or fail. Even with the good adhesion of the lap splice, the cords adjacent the splice tended to be stretched compensating for the overlapped two layers of cords at the splice. This localized stretching creates a non-uniformity that is readily visible under x-ray, ultrasonic display or by physically cutting the tire and visually inspecting it.
The tire designer, in order to prevent the creation of tire uniformity problems, has historically insured that the splices of various layers of components were not circumferentially aligned. This non-alignment of splice joints was believed to improve the carcass overall durability and uniformity, as measured by the amount of force variation and the balance of the tire. Tire engineers also have believed that tire uniformity could be improved if these discontinuities were deliberately circumferentially spaced around the carcass. This meant that each component had to be applied to the ply at the tire building station where each component was cut and spliced in a spaced order.
When the cord reinforced plies are placed on the building drum, it is very important that the geometric spacing of the beads and the ply turnups are controlled a uniformly. Variations in the overall tire building process can result in variations in cord tension. These non-uniformities can affect the ride and handling characteristics of the tire.
In U.S. Pat. No. 6,250,356 to Michelin, a tire assembly drum is disclosed wherein the beads are two distinct sizes. Conventionally, tires are symmetrical having equal bead diameters. The two distinct diameters on a tire exacerbate the problems of tire building and the disclosed assembly drum provides a method and apparatus to permit the tire to be built in a more uniform and faster way. This building drum was designed to build tires having a given set of two different diameters at the first stage of assembly. A separate tire-shaping drum was used to toroidally shape the tire carcass to assemble the tread and belt reinforcements and that drum is disclosed in U.S. Pat. No. 6,234,227.
The present invention has the objective of providing a building drum that is radially expansible and capable of building tires of equal bead diameters or of different bead diameters over a range of diameter sizes. In one embodiment, the building drum further has the objective of having axially movable ends, which can be air tightly sealed to permit the assembled carcass to be inflated and shaped toroidally, avoiding removal from the assembly drum for a second stage of tire building.
SUMMARY OF THE INVENTION
An improved radially expansible assembly drum for the manufacture of tires is disclosed. The assembly drum has a body mounted on a drum core assembly and presenting a receiving surface for tire components to be assembled. The ends and the receiving surface have the same or different diameters. A means for covering the ends of the receiving surface and a means for radially expanding the drum are also provided. The means for radially expanding the drum includes the ability to radially expand the receiving surface at the center and the ends of the assembly drum.
The radially expansible assembly drum has the means for radially expanding the assembly drum, including a cam disk having an increasing spiral cam follower groove. The cam follower groove provides a continuous range of selectable diameters and stable expansion of the drum diameters as a function of cam disk rotation. The spiral cam follower groove radially increases or decreases, dependent on the direction of rotation, causing an increase or a decrease in diametrical expansion or contraction at a rate of 40 mm per 360° of rotation of the assembly drum. The continuous range of selectable diameters increases from a diameter of d
i
to a fully expanded diameter d
e
, d
e
being equal to or greater than d
i
+55 mm.
In one embodiment of the invention, the radially expandable assembly drum has a means for axially moving the ends of the assembly drum, the ends being simultaneously movable from an axially widely spaced location to an axially inner location closer to a centerline of the assembly drum. This movement of the two ends is preferably equal in axial displacement. This reduction in axial space between the two ends permits the cords of the ply to be radially expanded and the assembled tire carcass to be toroidally shaped to permit the tread and reinforcing belt structure to be assembled while the assembled tire is held on the radially expansible assembly drum.
The multi-movement capability of the assembly drum is achieved by this unique drum core assembly. The drum core assembly includes a spindle for rotating the assembly drum, a driving shaft which passes through the center of the spindle, and a first external shaft connected to the means for radially expanding the assembly drum. The first external shaft is parallel and eccentrically located relative to the centerline of the spindle. The driving shaft provides rotary motion to the first external shaft, via a first external clutch mechanism. The engagement of the first clutch mechanism rotates the first external shaft to initiate radial expansion or contraction of the drum assembly.
The drum core assembly further includes a second external shaft connected to the means for axially moving the ends of the assembly drum. The second external shaft is parallel to and eccentrically located relative to the centerline of the spindle. The second external shaft is connected to a second clutch mechanism. The engagement of the second clutch mechanism (to the driving shaft) rotates the second external shaft to initiate axial movement of the ends of the assembly drum.
The second external shaft has oppositely directed threads, one set of threads being connected to one end of the assembly drum, the oppositely directed threads being connected to the opposite end of the assembly drum. Rotation of the second external shaft in one rotating direction moves the ends of the assembly drum closer while an opposite rotation of the second external shaft moves the ends further ap
Currie William Dudley
Lundell Dennis Alan
Weaver Douglas Raymond
King David L.
Knable Geoffrey L.
Rickey June E.
The Goodyear Tire & Rubber Company
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